Transmitting One Qubit Can Increase One Ebit Between Two Parties at Most

Abstract

Entanglement shared between two seperated parties could not be increased without transmitting quantum system. We suggest the project to gain entanglement shared between Alice and Bob by transmitting quantum system and a nem scheme to achieve efficient rate of entanglement. It is proven that under any local operations and communicating classically, to transmit one qubit through an ideal or a noisy quantum channel can increase no more than one ebit between two parties. Furthermore, the prior nonmaximally transmitted entanglement could not be improved by subsequently transmitted qubit. Although our proof is given in the measure of formation of entanglement, we believe that the above conclusion is also hold independently of the measure of entanglement.